Protection in metro optical networks

ABSTRACT

An optical network is configured to optimize network resources. The optical network includes multiple optical nodes, light paths between the multiple optical nodes, and a network monitoring device. The network monitoring device monitors the optical network to identify a failure in the optical network. When the failure is a fiber failure, light paths are re-routed around the fiber failure while maintaining the required bandwidth for the optical network. When the failure is a transponder card failure within one of the multiple nodes, a floating spare card may be provisioned to service a particular light path associated with the transponder card failure. When the failure is a node failure, transponder cards in some of the multiple optical nodes are provisioned to reconfigure some of the plurality of light paths to route traffic around the failed node.

BACKGROUND

Routing video, data, and voice traffic at high bit rates via Ultra LongHaul (ULH) or metro optical networks is substantially increasing inmodern communications systems. Some variants of such systems transmitoptical signals through optical fibers via dense wavelength divisionmultiplexing (DWDM), in which multiple wavelengths of light aretransmitted simultaneously through a single fiber. DWDM systemstypically employ devices called reconfigurable optical add/dropmultiplexers (ROADMs) to add and remove signals from the network in apurely optical manner, without requiring conversion to/from theelectrical domain.

In a typical metro optical network architecture, traffic protectionagainst various network failures is provided by doubling the networkcapacity over the projected traffic (also referred to as 1+1 protectionarchitecture). Thus, the typical architecture offers an inefficient useof resources and limits network growth.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram illustrating an exemplary environment in whichsystems and methods described herein may be implemented;

FIG. 2 is a diagram illustrating an exemplary embodiment of an opticalnode of FIG. 1;

FIG. 3 is a diagram illustrating an exemplary embodiment of an add-dropmultiplexer that may be included in the optical node of FIG. 2;

FIG. 4 is a schematic diagram of an exemplary portion of the opticalnetwork of FIG. 1;

FIG. 5 is a flow diagram illustrating an exemplary process to manage anoptical network;

FIG. 6A is a schematic diagram of a card failure protection scheme inthe portion of the optical network of FIG. 4;

FIG. 6B is a schematic diagram of a fiber failure protection scheme inthe portion of the optical network of FIG. 4; and

FIG. 6C is a schematic diagram of a node failure protection scheme inthe portion of the optical network of FIG. 4.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The following detailed description refers to the accompanying drawings.The same reference numbers in different drawings may identify the sameor similar elements.

Systems and methods described herein may provide an optical networkconfigured to optimize network resources. The optical network mayinclude multiple optical nodes, light paths between the multiple opticalnodes, and a network monitoring device. The network monitoring devicemay monitor the optical network to identify a failure in the opticalnetwork. When the failure is a fiber failure, light paths may bere-routed around the fiber failure while maintaining the requiredbandwidth for the optical network. When the failure is a transpondercard failure within one of the multiple nodes, a floating spare card maybe provisioned to service a particular light path associated with thetransponder card failure. When the failure is a node failure,transponder cards in some of the multiple optical nodes may beprovisioned to reconfigure some of the plurality of light paths to routetraffic around the failed node. The systems and method described hereinmay be used to reduce idle capacity required in typical protectionschemes and reduce capital expenditures for hardware such as gray opticsand transponder cards.

FIG. 1 is a diagram illustrating an exemplary environment of an opticalnetwork in which systems and methods described herein may beimplemented. As illustrated in FIG. 1, an exemplary environment 100includes an optical network 105 including optical node 110-1 throughoptical node 110-X, in which X>1 (referred to individually as “opticalnode 110” or collectively as optical nodes 110), optical link 115-1through optical link 115-Y, in which Y>1 (referred to individually asoptical link 115 or collectively as optical links 115), and networkmanagement system 120. Environment 100 also includes device 125-1through device 125-Z, in which Z>1 (referred to individually as device125 or collectively as devices 125). Devices 125 may be communicativelycoupled to optical network 105 via various access technologies.

The number of devices (which includes optical nodes) and theconfiguration in environment 100 are exemplary and provided forsimplicity. According to other embodiments, environment 100 may includeadditional devices, fewer devices, different devices, and/ordifferently-arranged devices than those illustrated in FIG. 1. Forexample, environment 100 may include intermediary devices (notillustrated) to permit communication between devices 125 and opticalnetwork 105.

Optical network 105 may include, for example, a synchronous opticalnetwork or other types of optical networks. Optical network 105 may beimplemented using various topologies (e.g., mesh, ring, etc.). Accordingto an exemplary embodiment, optical network 105 is a long-haul opticalnetwork (e.g., long-haul, extended long-haul, ultra long-haul). In oneimplementation, optical network 105 may be implemented as an agilephotonic network that uses flexible end-to-end channel allocation.According to aspects described herein, an agile photonic network may beconfigured to reduce capital costs over conventional optical networks.Generally, optical network 105 may enable activation of wavelengths froman optical node 110 to any other optical node 110 and may automaticallyprovision light paths to route around points of failure.

Optical node 110 is a point in optical network 105. For example, opticalnode 110 may be an aggregation node (e.g., that does not communicatedirectly with other aggregation nodes) or a core node (e.g., that passescommunications from/to aggregation nodes). Optical node 110 may beimplemented as a DWDM system. Optical link 115 is an optical fiber(e.g., nonzero dispersion-shifted fiber, etc.) that communicativelycouples one optical node 110 to another optical node 110.

Network management system 120 may manage the configuration of opticalnetwork 105 including the optical nodes 110. Network management system120 may permit administrators to monitor, configure, etc., opticalnetwork 105. Network management system 120 may be capable of identifyingnetwork state information, resource availability, resource allocation,and/or other parameters pertaining to optical network 105. Networkmanagement system 120 may communicate with a network management module(e.g., network management module 240 in FIG. 2) of an optical node 110regarding these parameters as such parameters relate to the featuresdescribed herein. For example, network management system 120 may monitoroptical network 105 for failures and direct corrective action to avoidcommunication disruptions. In one aspect, as described further herein,network management system 120 may initiate or suggest re-routing oflight paths around a failed node or fiber failure. In another aspect, asalso described further herein, network management system 120 mayinitiate or suggest provisioning a spare transponder card to replace afailed card and/or interface. Network management system 120 may includeone or more network devices (e.g., a server, a computer, etc.) includingvarious memories and/or processors. Network management system 120 may beimplemented in a centralized or a distributed fashion.

Device 125 may include a device having the capability to communicatewith a network (e.g., optical network 105), devices and/or systems. Forexample, device 125 may correspond to a user device, such as a portabledevice, a handheld device, a mobile device, a stationary device, avehicle-based device, or some other type of user device. Additionally,or alternatively, device 125 may correspond to a non-user device, suchas, a meter, a sensor, or some other device that is capable ofmachine-to-machine (M2M) communication.

FIG. 2 is a diagram illustrating components of an exemplary embodimentof optical node 110 depicted in FIG. 1. As shown in FIG. 2, optical node110 may include a reconfigurable optical add/drop multiplexer (ROADM)210, a transponder chassis 220, a data switch 230, and a networkmanagement module 240.

ROADM 210 can remotely switch traffic that was transmitted using WDM orDWDM at the wavelength layer. According to one implementation, ROADM 210may include a colorless (e.g., any wavelength to any add/drop port), adirectionless (e.g., any wavelength to any degree), a contentionless(e.g., any combination of wavelengths to any degree from any port), anda gridless (e.g. no fixed frequency) architecture. ROADM 210 may supportany portion of the optical spectrum provided by optical network 105, anychannel bit rate, and/or any modulation format. ROADM 210 may employagile photonic connections 212 that enable changes in trunk connectivityfrom one transponder card to a floating transponder card withoutphysically re-connecting the floating transponder card to a new port.ROADM 210 is described further in connection with FIG. 3.

FIG. 3 is a diagram illustrating an exemplary embodiment of ROADM 210that may be included in one or more of optical nodes 110. Asillustrated, ROADM 210 may include, among other components, flexiblespectrum selective switches (FSSSs) 305-1 through 305-4 (referred toindividually as FSSS 305 or collectively as FSSSs 305), power splitters310-1 through 310-4 (referred to individually as power splitter 310 orpower splitters 310), and add/drop ports 315. According to otherembodiments, ROADM 210 may have a different degree (i.e., other than a4-degree ROADM).

The number of components and the configuration (e.g., connection betweencomponents) show in FIG. 3 are exemplary and provided for simplicity.According to other embodiments, ROADM 210 may include additionalcomponents, fewer components, different components, and/ordifferently-arranged components than those illustrated in FIG. 3. Forexample, ROADM 210 may include a channel monitor and/or an errordetector. According to an exemplary implementation, ROADM 210 may takethe form of a ROADM blade. According to an exemplary embodiment, ROADM210 is colorless, directionless, contentionless, and gridless.

FSSS 305 may include a spectrum selective switch that, among otherthings, may be able to switch any optical channel regardless of itsbandwidth and central frequency. FSSS 305 may also have grid-freecapability. FSSS 305 may also accommodate other features pertaining tothe optical network described herein. In this regard, FSSS 305 may bedistinguishable from a Wavelength Selective Switch (WSS) that is used ina conventional ROADM. Power splitter 310 may include an optical powersplitter and/or an optical power combiner that is/are color-agnostic,directionless, and contentionless. Power splitter 310 may provide forsplitting and/or combining of optical signals in optical fibers.Add/drop ports 315 are ports for adding and dropping optical signals.

ROADM 210 (e.g., FSSS 305) is capable of using the available spectralbandwidth in a colorless, directionless, contentionless, and gridlessframework. Additionally, as previously described, ROADM 210 may switchwavelengths flexibly among transponder cards. In other aspects, thetotal number of optical channels in the transport system is not fixed,the data rate of each optical channel is not fixed, the number ofoptical carriers for each optical channel is not fixed, the centralfrequency of an optical channel is not adherent to a fixed frequencygrid, and the bandwidth and the number of optical carriers of eachoptical channel may be dynamically adjusted based on network trafficdemands, available resources, etc.

Returning to FIG. 2, transponder chassis 220 generally includesequipment to convert signal formats between client signals (to/from dataswitch 230) and trunk signals (from/to ROADM 210). Client-facing “gray”optical signals generally operate at shorter wavelengths, whereas trunksignals include DWDM “colored” optical signals in a longer wavelengthrange. Transponder chassis 220 may include multiple transponder cards222. Each transponder card 222 may be configured to convert gray opticalclient interface signals (e.g., from switch 230) into trunk signals thatoperate in the colored DWDM wavelengths used by ROADM 210. Conversely,transponder card 222 may also convert signals in the “colored” DWDMwavelengths from ROADM 210 to “gray” optical client interface signalsthat may be used by switch 230. Each transponder card 222 may include,for example, a gray optics module 224 and a line optical module 226coupled by a processor 228 that converts signals for gray optics module224 and line optical module 226. For example, processor 228 may includelogic to convert optical signals from line optical module 224 toconstruct frames, packets, or other type of data containers for grayoptics module 224.

In one implementation, transponder card 222 may include a 100-Gbps(gigabytes per second) multirate transponder card. Thus, in thisimplementation, transponder card 222 may processes a 100-Gbps signal onthe client side into one 100-Gbps DWDM signal on the trunk side.According to implementations described herein, transponder chassis maybe configured with multiple transponder cards that can be provisioned(e.g., tuned for a particular wavelength) without the presence ofon-site personnel.

Data switch 230 may include a data transfer device, such as a router, aswitch (e.g., multiprotocol label switching (MPLS) switch), a gateway, adevice providing domestic switching capabilities, or some other type ofdevice that processes and/or transfers data. In one implementation, dataswitch 230 may operate on data on behalf of a network providing datato/from client devices 125 and may serve as an entrance to opticalnetwork 105. In one implementation, data switch 230 may include multiplegray optics modules 232, each of which may communicate with one oftransponder cards 222 via a switch-transponder interface 234.

Network management module 240 may include one or multiple processors,microprocessors, multi-core processors, application specific integratedcircuits (ASICs), controllers, microcontrollers, and/or some other typeof hardware logic to perform the processes or functions describedherein. Network management module 240 may configure the operation ofoptical node 110 based on information received from network managementsystem 120 and/or optical network requirements (e.g., network trafficdemands, resources available, interruptions/failures, etc.). Forexample, network management module 240 may identify a network failure,tune (or direct tuning of) a spare transponder card 222 within node 110,and/or re-arrange a light path between nodes 110 to prevent trafficdisruptions. Network management module 240 may also correlateperformance and alarm information across all optical carriers. Networkmanagement module 240 may include one or multiple processors,microprocessors, multi-core processors, application specific integratedcircuits (ASICs), controllers, microcontrollers, and/or some other typeof hardware logic to perform the processes or functions describedherein.

Generally, a transmitting-side of optical node 110 may output opticalsignals to optical links 115, which may traverse light paths in opticalnetwork 105. A receiving-side of optical nodes 110 may be configuredboth in terms of operation and available node resources for fullbandwidth utilization.

According to implementations described herein, one or more transpondercards 222 may be used as a “floating” transponder card, such that thewavelength of the floating transponder card 222 can be tuned to replaceany one of the other transponder cards 222. Upon network managementmodule 240 detecting a failure of one of transponder cards 222, thefloating transponder card 222 may be automatically configured to replacethe failed transponder card 222 within transponder chassis 230. Theapplication of a single floating transponder card (or any amount offloating transponder cards less than the total amount of active cards)in optical nodes 110 can significantly reduce idle capacity in opticalnetwork 105. For example, the number of unused and/or under-utilizedgray optics modules 224/232 and line optical modules 226 may be reducedto as few as a single spare in each optical node 110, while theremaining active components may operate at or near one hundred percentcapacity, when required.

For a single node with individual card failures, one floatingtransponder card 222 can generally provide sufficient protection toachieve required reliability metrics (e.g., 99.99%). If there is aprobability of multiple card failures in a single optical node 110, morethan one floating transponder card 222 may be used. However, theprobability of multiple simultaneous card failures in most optical nodeapplications would be so small as to not affect reliabilitycalculations. If the total number of floating transponder cards 222 andactive transponder cards 222 are not enough to support all workingconnections during an event where an entire core node is disabled,additional floating transponder cards may be implemented in the corenodes of a particular optical network while a single floatingtransponder card may provide adequate protection for aggregation nodes.

The number of components and the configuration (e.g., connection betweencomponents) shown in FIG. 2 are exemplary and provided for simplicity.According to other embodiments, optical node 110 may include additionalcomponents, fewer components, different components, and/ordifferently-arranged components than those illustrated in FIG. 2. Forexample, optical node 110 may include a laser, a power source, anoptical amplifier (e.g., Erbium Doped Fiber Amplifier (EDFA), Ramanamplifier, etc.), digital signal processing (DSP) (e.g., forward errorcorrection (FEC), equalization, filtering, etc), etc.

FIG. 4 provides a simplified schematic of a portion 400 of opticalnetwork 105 configured according to an implementation described herein.As shown in FIG. 4, network portion 400 may include a ring topology withsix optical nodes 110, two of which are core nodes (e.g., 110-C1 and110-C2) and four of which are aggregation nodes (e.g., 110-A1, 110-A2,110-A3, and 110-A4). Each optical node (e.g., 110-C1, 110-C2, 110-A1,110-A2, 110-A3, and 110-A4) may include a ROADM 210, a transponderchassis 220, a data switch 230, and a network management module 240 (notshown in FIG. 4), as described above in connection with FIG. 2.

In the configuration of FIG. 4, traffic does not flow directly betweenaggregation nodes (e.g., directly from nodes 110-A1 to 110-A2, etc.).Thus, traffic patterns in network portion 400 may include links betweencore nodes 110-C1 and 110-C2 and links between core nodes 110-C1/110-C2and any of aggregation nodes 110-A1 through 110-A4. Assume networkportion 400 is configured to meet an initial traffic demand of 1200Gbps. Particularly, the initial traffic demand between nodes 110-C1,110-C2, 110-A1, 110-A2, 110-A3, and 110-A4 may be defined as shown inTable 1.

TABLE 1 Initial Traffic Demand between Nodes (Gbps) NODE C1 C2 A1 A2 A3A4 C1 — 400 100 100 100 100 C2 — — 100 100 100 100 A1 — — —  0  0  0 A2— — — —  0  0 A3 — — — — —  0 A4 — — — — — —

To support the required traffic demand, according to one embodiment,each core node (e.g., 110-C1 and 110-C2) may include nine 100 Gbps cardsets. Eight card sets may be provisioned to support the traffic demandfor the core node (e.g., 800 Gbps total) and one card set may beinstalled as a floating transponder card set (e.g., 100 Gbps).Additionally, each aggregation node (e.g., 110-A1 through 110-A4) mayinclude three card sets of 100 Gbps line cards and 100 Gbps gray opticsmodules. Two card sets may be provisioned to support the traffic demandfor the aggregation node (e.g., 200 Gbps total) and one card set may beinstalled as a floating transponder card set (e.g., 100 Gbps).Particularly, each card set would include a line optical module 226 anda gray optics module 224 paired to a gray optics module 232.

Generally, according to implementations described herein, networkportion 400 may be configured to provide a required bandwidth with noadditional wavelength reservation for protection (e.g., full bandwidthutilization). Each of the optical nodes 110 may include card sets (e.g.,line optical module 226 and a gray optics module 224 paired to a grayoptics module 232) with a majority (e.g., two or more) of the card setsprovisioned as active cards to receive a traffic load of up to fullcapacity of the card sets and a minority (e.g., as few as one) of thecard sets provisioned as floating spare cards for the active cards.

In the configuration of FIG. 4, network portion 400 may support anoverall traffic capacity of 1200 Gbps, with reliable backup capacity,while using significantly less dedicated hardware than a typical 1+1protection architecture. Particularly, the configuration of networkportion 400 may use a total of thirty 100 Gbps card sets (e.g.,twenty-four active card sets with six floating backup card sets)distributed among nodes 110-C1, 110-C2, 110-A1, 110-A2, 110-A3, and110-A4 (with each card set including a line optical module 226, a grayoptics module 224, and a gray optics module 232). By contrast, a typical1+1 protection architecture for the same capacity and traffic patternwould require a total of forty-eight 100 Gbps card sets (e.g.,twenty-four active card sets with twenty-four fixed backup card sets)distributed among nodes 110-C1, 110-C2, 110-A1, 110-A2, 110-A3, and110-A4.

Protection of network portion 400 may include protection from cardfailures within nodes, fiber failures between nodes, and node failures.Individual card failures within an optical node 110 (e.g. failure of aline optical module 226, a gray optics module 224, or a gray opticsmodule 232) may prevent communications between two particular nodes 110.Fiber failures (e.g., a fiber cut) may disrupt communications betweenmultiple nodes 110. Node failures may disrupt communications to thefailed node 110 and light paths that pass through the failed node 110.Network management system 120 and/or the network management modules 240in each node 110 may monitor network portion 400 for failures/alarms dueto card failures within nodes, fiber failures between nodes, and nodefailures. For example, network management modules 240 may detect a localfailure or series of transmission time-outs for an individual card setor multiple card sets. Additionally, or alternatively, networkmanagement system 120 may receive input from multiple network managementmodules 240 to determine a mode of failure, such as failedcommunications along multiple light paths that are indicative of a fiberfailure or multiple card failures at a single optical node 110 that areindicative of a node failure.

Network management system 120 and/or the network management modules 240may initiate reconfiguration of light paths and/or card sets to avoidtraffic disruptions until, for example, additional network repairs(e.g., by a service technician) can be provided to restore failedcomponents.

Although FIG. 4 show exemplary components of network portion 400, inother implementations, network portion 400 may include fewer components,different components, differently-arranged components, and/or additionalcomponents than depicted in FIG. 4. Alternatively, or additionally, oneor more components of network portion 400 may perform one or more othertasks described as being performed by one or more other components ofnetwork portion 400.

FIG. 5 is a flow diagram illustrating an exemplary process 500 to managean optical network according to an implementation described herein.According to an exemplary embodiment, process 500 may be performed bynetwork management system 120. According to another embodiment, theexemplary processes may be performed by a combination of networkmanagement system 120 and network management module 240. According toyet another exemplary embodiment, the exemplary processes may beperformed by network management module 240.

Parts of process 500 are described below in connection with FIGS. 4 and6A-6C. FIG. 6A is a schematic diagram of a card failure protectionscheme in network portion 400. FIG. 6B is a schematic diagram of a fiberfailure protection scheme in network portion 400. FIG. 6C is a schematicdiagram of a node failure protection scheme in t network portion 400.

As shown in FIG. 5, process 500 may include monitoring an opticalnetwork having a required bandwidth with no additional wavelengthreservation for protection and multiple optical nodes (block 510). Forexample, as shown in FIG. 4, network portion 400 may include multiplecore nodes 110 and aggregation nodes 110 connected by light paths withno additional wavelength reservation. Each node may include transpondercards with a majority of the transponder cards provisioned as activecards to receive a traffic load of up to full capacity of the card setsand a minority of the transponder cards provisioned as floating sparecards for the active cards. In the configuration of FIG. 4, each nodemay include a single floating transponder card set 222. However,additional floating card sets (e.g., a minority less than the number ofactive card sets) may be used at particular nodes.

Process 500 may also include identifying a failure in the opticalnetwork (block 520). For example, network management system 120 mayidentify one of a transponder card failure, a fiber failure, or a nodefailure. In one implementation, network management modules 240 mayindicate a local failure or transmission time-out for an individual cardset or multiple card sets. In another implementation, network managementsystem 120 may receive input from multiple network management modules240 to determine a mode of failure. For example, network managementsystem 120 may identify failed communications along multiple light pathsto determine a fiber failure. Alternatively, network management system120 may identify multiple card failures at a single optical node 110 todetect a node failure.

Process 500 may further include provisioning, when the failure is atransponder card failure, one of the floating spare cards in a node withthe failed transponder card to service the particular light pathassociated with the failed transponder card, and routing the light pathassociated with the failed transponder card to the one of the floatingspare cards (block 530). For example, referring to FIG. 6A, a singlecard (e.g., a transponder card 222 or a switch gray optics module 232)or an interface (e.g., a switch-transponder interface 234) within node110-C1 may fail, causing an interruption in the light path between node110-A1 and node 110-C1. Floating transponder card 222-S at node 110-C1may be used to replace the failed card/interface. ROADM 210-C1 maydirect a new light path 610 (e.g., using the same wavelength that waspreviously reserved for the failed card) from floating transponder card222-S to the corresponding transponder card at node 110-A1. Thetransition from the failed card to floating transponder card 222-S innode 110-C1 may be performed without physical intervention from atechnician.

Process 500 may additionally include routing, when the failure is afiber failure, traffic around the fiber failure while maintaining therequired bandwidth (block 540). For example, referring to FIG. 6B afiber cut is detected between node 110-C1 and node 110-A1. The fiber cutinterrupts all light paths traversing between node 110-C1 and node110-A1. New light paths may be provisioned to avoid the fiber cut usingthe same wavelengths that were previously used for the failed paths. Forexample, new light path 615 through nodes 110-A1, 110-A2, 110-C2,110-A4, 110-A3, and 110-C1 may replace the failed light path betweennodes 110-A1 and 110-C1. Similarly, new light path 620 through nodes110-A2, 110-C2, 110-A4, 110-A3, and 110-C1 may replace the failed lightpath through nodes 110-A2, 110-A1, and 110-C1. Additionally, new lightpaths 625 and 630 through nodes 110-C1, 110-A3, 110-A4, and 110-C2 mayreplace the failed light path through nodes 110-C1, 110-A1, 110-A2, and110-C2. The re-routing of the new light paths may be performed withoutphysical intervention from a technician.

Process 500 may also include provisioning, when the failure is a nodefailure, at least some of the transponder cards in some of the opticalnodes to reconfigure at least some of the plurality of light paths toroute traffic around the failed node (block 550). For example, referringto FIG. 6C, a failure of node 110-C1 may be detected. The node failureinterrupts all light paths light paths traversing between node 110-C1and node 110-A1 and traversing between nodes 110-C1 and 110-A3. Newlight paths may be provisioned to avoid the failed node. As shown inFIG. 6C, transponders in node 110-C2 that were previously used forcore-to-core communications (e.g., between node 110-C1 and node 110-C2)may be re-provisioned for aggregation-to-core communications (e.g.,between node 110-C2 and each of the aggregation nodes 110-A1, 110-A2,110-A3, and 110-A4). In some cases, some transponder cards in theremaining nodes (e.g., nodes 110-A1, 110-A2, 110-A3, 110-A4, and 110-C2)may be re-provisioned with different wavelengths than were previouslyused for the failed paths.

For example, new light path 635 through nodes 110-A1, 110-A2, and 110-C2may replace the failed light path between nodes 110-A1 and 110-C1 (e.g.,using the wavelength originally provisioned for the light path betweennodes 110-A1 and 110-C1). New light path 640 through nodes 110-A2 and110-C2 may replace the failed light path through nodes 110-A2, 110-A1,and 110-C1 (e.g., using the wavelength originally provisioned for thelight path between nodes 110-A2, 110-A1, and 110-C1). Additionally, newlight path 645 through nodes 110-A3, 110-A4, and 110-C2 may replace thefailed light path between nodes 110-A3 and 110-C1 (e.g., using thewavelength originally provisioned for the light path between nodes110-A3 and 110-C1); and new light path 650 through nodes 110-A4 and110-C2 may replace the failed light path through nodes 110-A4, 110-A3,and 110-C1 (e.g., using the wavelength originally provisioned for thelight path between nodes 110-A4, 110-A3, and 110-C1).

Although FIG. 5 illustrates an exemplary process 500 to manage anoptical network, according to other implementations, process 500 mayinclude additional operations, fewer operations, and/or differentoperations than those illustrated in FIG. 5 and described.

The foregoing description of implementations provides illustration, butis not intended to be exhaustive or to limit the implementations to theprecise form disclosed. Accordingly, modifications to theimplementations described herein may be possible.

According to an exemplary embodiment described, a method may includeconfiguring an optical network for a required bandwidth. The network mayinclude multiple optical nodes and a plurality of light paths betweenthe multiple optical nodes. The multiple optical nodes may includetransponder cards with a majority of the transponder cards provisionedas active cards to receive a traffic load of up to full capacity of thecard sets and with a minority of the transponder cards provisioned asfloating spare cards for the active cards. A network management devicemay identify a failure in the optical network as one of a transpondercard failure, a fiber failure, or a node failure. When the failure is atransponder card failure, the network management device may provisionone of the floating spare cards in a node with the failed transpondercard to service the particular light path associated with the failedtransponder card, and route the light path associated with the failedtransponder card to the one of the floating spare cards. When thefailure is a fiber failure, the network management device may re-routetraffic around the fiber failure while maintaining the requiredbandwidth. When the failure is a node failure, the network managementdevice may provision at least some of the transponder cards in some ofthe optical nodes to reconfigure at least some of the plurality of lightpaths to route traffic around the failed node.

According to implementations described herein, the optical network mayprovide savings in gray optics and transponder cards while eliminatingthe need to reserve idle capacity for traffic protection purposes. Theoptical network may be configured to use full wavelength spectrum tomeet bandwidth requirements for the network while requiring minimalspare cards.

The terms “a,” “an,” and “the” are intended to be interpreted to includeone or more items. Further, the phrase “based on” is intended to beinterpreted as “based, at least in part, on,” unless explicitly statedotherwise. The term “and/or” is intended to be interpreted to includeany and all combinations of one or more of the associated items.

In addition, while a series of blocks is described with regard to theprocesses illustrated in FIG. 5, the order of the blocks may be modifiedin other implementations. Further, non-dependent blocks may be performedin parallel. Additionally, with respect to other processes described inthis description, the order of operations may be different according toother implementations, and/or operations may be performed in parallel.

An embodiment described herein may be implemented in many differentforms of software and/or firmware executed by hardware. For example, aprocess or a function may be implemented as “logic” or as a “component.”The logic or the component may include, for example, hardware, acombination of hardware and software, a combination of hardware andfirmware, or a combination of hardware, software, and firmware. By wayof example, hardware may include a processor. The processor may include,for example, one or multiple processors, microprocessors, dataprocessors, co-processors, multi-core processors, application specificintegrated circuits (ASICs), controllers, programmable logic devices,chipsets, field programmable gate arrays (FPGAs), system on chips(SoCs), programmable logic devices (PLSs), microcontrollers, applicationspecific instruction-set processors (ASIPs), central processing units(CPUs) to interpret and/or execute instructions and/or data.

In the preceding specification, various embodiments have been describedwith reference to the accompanying drawings. It will, however, beevident that various modifications and changes may be made thereto, andadditional embodiments may be implemented, without departing from thebroader scope of the invention as set forth in the claims that follow.The specification and drawings are accordingly to be regarded asillustrative rather than restrictive.

In the specification and illustrated by the drawings, reference is madeto “an exemplary embodiment,” “an embodiment,” “embodiments,” etc.,which may include a particular feature, structure or characteristic inconnection with an embodiment(s). However, the use of the phrase or term“an embodiment,” “embodiments,” etc., in various places in thespecification does not necessarily refer to all embodiments described,nor does it necessarily refer to the same embodiment, nor are separateor alternative embodiments necessarily mutually exclusive of otherembodiment(s). The same applies to the term “implementation,”“implementations,” etc.

No element, act, operation, or instruction described in the presentapplication should be construed as critical or essential to theembodiments described herein unless explicitly described as such.

What is claimed is:
 1. A method comprising: configuring an opticalnetwork for a required bandwidth, wherein the network configurationincludes multiple optical nodes and a plurality of light paths betweenthe multiple optical nodes, and wherein the multiple optical nodesinclude transponder cards with a majority of the transponder cardsprovisioned as active cards to receive a traffic load of up to fullcapacity of the card sets, and with a minority of the transponder cardsprovisioned as floating spare cards for the active cards; identifying,by a network management device, a failure in the optical network as oneof a transponder card failure, a fiber failure, or a node failure;automatically provisioning, by the network management device and whenthe failure is a transponder card failure, one of the floating sparecards in a node with the failed transponder card to service theparticular light path associated with the failed transponder card, androuting the light path associated with the failed transponder card tothe one of the floating spare cards; re-routing, by the networkmanagement system and when the failure is a fiber failure, trafficaround the fiber failure while maintaining the required bandwidth; andprovisioning, by the network management device and when the failure is anode failure, at least some of the transponder cards in some of theoptical nodes to reconfigure at least some of the plurality of lightpaths to route traffic around the failed node.
 2. The method of claim 1,wherein the transponder card failure includes a failure to one of atransponder line optical module, a transponder gray optics module, aswitch gray optics module or a switch-transponder interface associatedwith a single light path.
 3. The method of claim 1, wherein, whenre-routing the traffic around the fiber failure, the re-routed trafficuses light paths having the same wavelength as those interrupted by thefiber failure.
 4. The method of claim 1, wherein, when provisioning atleast some of the transponder cards in some of the optical nodes toreconfigure at least some of the plurality of light paths to routetraffic around the failed node, the at least some of the transpondercards are provisioned to use wavelengths previously assigned forcommunications with the failed node.
 5. The method of claim 1, whereinthe multiple nodes include core nodes and aggregation nodes and whereinthe optical network is configured such that traffic does not flowdirectly between aggregation nodes.
 6. The method of claim 1, whereinthe light paths do not include additional wavelengths reserved forprotection of the required bandwidth.
 7. The method of claim 1, whereinthe minority of the transponder cards provisioned as floating sparecards includes no more than two floating spare cards at each of themultiple optical nodes.
 8. The method of claim 7, wherein the minorityof the transponder cards provisioned as floating spare cards includeexactly one floating spare cards at each of the multiple optical nodes.9. The method of claim 1, wherein the optical network is a long-hauloptical network.
 10. The method of claim 1, wherein each of the multipleoptical nodes includes a reconfigurable optical add/drop multiplexer(ROADM) with a colorless, directionless, and contentionlessarchitecture.
 11. The method of claim 10, wherein each of the multipleoptical nodes includes a transponder chassis and a data switch.
 12. Aoptical network, comprising: multiple optical nodes with a plurality oflight paths between the multiple optical nodes; and a network monitoringdevice including one or more processors configured to: monitor theoptical network, identify a failure in the optical network, re-route,when the failure is a fiber failure, one or more of the plurality oflight paths around the fiber failure while maintaining the requiredbandwidth for the optical network, provision, when the failure is atransponder card failure within one of the multiple nodes, a floatingspare card in the one of the multiple nodes to service a particularlight path associated with the transponder card failure, and route theparticular light path to the floating spare card, and provision, whenthe failure is a node failure, transponder cards in some of the multipleoptical nodes to reconfigure some of the plurality of light paths toroute traffic around the failed node.
 13. The device of claim 12,wherein each of the multiple optical nodes include a majority of thetransponder cards provisioned as active cards to receive a traffic loadof up to full capacity of the card sets and a minority of thetransponder cards provisioned as floating spare cards for the activecards.
 14. The network management system of claim 12, wherein theplurality of light paths between the multiple optical nodes support arequired bandwidth when the light paths are used at full capacity. 15.The network management system of claim 12, wherein each of the opticalnodes includes multiple transponder cards and the floating spare card.16. The network management system of claim 12, wherein the transpondercard failure includes a failure to one of a transponder line opticalmodule, a transponder gray optics module, a switch gray optics module ora switch-transponder interface associated with a single light path. 17.The network management system of claim 12, wherein, when re-routing theone or more of the plurality of light paths around the fiber failure,the network management system is further configured to: use light pathshaving the same wavelength as those interrupted by the fiber failure.18. The network management system of claim 12, wherein, whenprovisioning transponder cards in some of the multiple optical nodes toreconfigure some of the plurality of light paths to route traffic aroundthe failed node, the network management system is further configured to:use wavelengths previously assigned for communications with the failednode.
 19. A network monitoring device for an optical network,comprising: a memory to store a plurality of instructions; and one ormore processors configured to: monitor the optical network including aplurality of light paths, identify a failure in the optical network asone of a fiber failure, a transponder card failure within one ofmultiple nodes, or a node failure, when the failure is a fiber failure,re-route one or more of the plurality of light paths around the fiberfailure while maintaining the required bandwidth for the opticalnetwork, when the failure is a transponder card failure, provision afloating spare card in the one of the multiple nodes to service aparticular light path associated with the transponder card failure androute the particular light path to the floating spare card, and when thefailure is a node failure, provision transponder cards in some of themultiple optical nodes to reconfigure some of the plurality of lightpaths to route traffic around the failed node.
 20. The networkmonitoring device of claim 19, wherein the plurality of light pathssupport a required bandwidth for the optical network when the lightpaths are used at full capacity.